To reduce fuel consumption, opportunities to reduce vehicle weight are widely sought. DE 10 2014 009 941 A1 proposes that conventional bumpers made of steel or aluminum be replaced by bumpers in which the crossbeam is formed of a fiber-reinforced plastic blank.
Crash boxes, which connect the crossbeam with the chassis of the vehicle are injection molded onto the crossbeam. They are open on the side facing the chassis and, because of the necessary demolding incline, their walls become thinner towards the chassis. Too thin a wall thickness encourages the crash boxes to break under pressure at the chassis-side end, rendering the bumper useless. Too thick a wall thickness prevents the buckling of the crash box at its bumper-side end which equally restricts its effectiveness.